Medium Chain Carboxylic Acids Production from Brewer’s Spent Grains supplemented with H2 and CO2 by a Mixed Microbial Culture
(2022) 2nd International Chain Elongation Conference — Location: Tubingen, Germany (2.November.2022)
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- Abstract
- Anthropogenic activities linked to our consumer society have led to the current environmental crisis. Mankind must move away from the sole use of non-renewable fossil resources and promote sustainable production of biobased chemicals and biofuels. The utilization of low-cost organic feedstocks, such as food wastes or agro-industrial residues are promising alternative to fossil resources in order to produce value added bio-based molecules. Mixed microbial fermentations can transform such feedstocks to short and medium chain carboxylates. These molecules have potential application in the pharmaceutical, chemical and biofuel sector. This study investigated the influence of the supplementation of H2 and CO2, in addition to the reducing equivalents and carbon fed by brewer’s spent grains, on the production of medium chain carboxylic acids by a mixed microbial culture. The fermentations were operated in triplicates for 21 days in batch mode under N2, H2, CO2 or H2/CO2 atmospheres, respectively. H2 promoted the MCCAs production, CO2 inhibited the global fermentation and the mixture H2/CO2 was the only condition that exhibited a second elongation phase. This second elongation phase led to an increase in MCCAs production by 211% and 385%, as compared to respectively the H2 reference and the N2 control conditions. A longer-term batch mode fermentation of 63 days under H2/CO2 atmosphere confirmed the fermentation profile and exhibited a MCCAs maximum concentration of 16.5±2.8 kgDCO/m3ML (11.6±1.8kg/m3ML) at day 42. Considering the sampling and refill of the mixed liquor, in order to keep a constant volume, a total MCCAs production of 25.6±4.0kgCOD/m³ML was achieved. Overall, this study demonstrated that H2 alone promotes the MCCAs production, CO2 alone inhibits the whole fermentation process, but when added together, H2 and CO2 chain elongation restarts.
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Henry, G., Isenborghs, A., & Gerin, P. (2022). Medium Chain Carboxylic Acids Production from Brewer’s Spent Grains supplemented with H2 and CO2 by a Mixed Microbial Culture. 2nd International Chain Elongation Conference, Tubingen, Germany. https://hdl.handle.net/2078.5/239326